1. Field of the Invention
The present invention relates to a desensitizer composition, more particularly, to a desensitizer composition capable of decreasing or halting the function of a color developing agent capable of causing color development on contact with a colorless color forming agent.
2. Development of the Invention
It is known that color images result on reactive contact of an electron donating or proton accepting colorless organic compound (hereinafter called a color forming agents) with an electron accepting or proton releasing solid acid (hereinafter called a color developing agent). Examples of using such reactions are common in the pressure sensitive copying paper art (see, e.g., U.S. Pat. Nos. 2,505,470; 2,505,489, 2,550,471; 2,548,366; 2,712,507; 2,730,456; 2,730,457; 3,418,250 and 3,672,935), in the heat sensitive recording paper (see, e.g., Japanese Patent Publication Nos. 4160/'68, 7600/'68 and 14039/'70; U.S. Pat. No. 2,939,009; etc.), etc.
In addition, a printing process where color images are obtained by applying a color forming agent containing ink to a color developing agent coated sheet is disclosed in German Patent Application (OLS) No. 1,939,962.
Color developing agents as above include clays, phenols, metalic salts of aromatic carboxylic acids, etc.
In general, such color developing agents are uniformly coated over the whole surface of a support, whereafter a printing machine or the like is used to apply a composition containing a desensitizer to only selected areas of the color developer sheet where images are not to be recorded for desensitization of the color developer sheet.
Various desensitizers are described in U.S. Pat. No. 2,777,780; Japanese Patent Publication Nos. 27255/'69, 21448/'70, 22651/'71 and 29546/'71; Japanese patent application (OPI) No. 32915/'72; Japanese Patent Publication Nos. 38201/'72 and 4050/'73; Japanese patent application (OPI) No. 6805/'73; Japanese Patent Publication Nos. 4484/'74, 19647/'74, 23008/'74 and 23850/'74; Japanese patent application (OPI) Nos. 43708/'74, 72009/'74, 77709/'74, 77710/'74, 15513/'74 and 83509/'74; German patent applications (OLS) Nos. 2,343,800, 2,359,079 and 2,361,856, these documents give specific examples of active desensitizers including quaternary ammonium salts such as dodecyltrimethylammonium chloride, octadecylammonium chloride and the like; amines of high molecular weight such as dodecyl amine and the like; substituted oxazolines such as 2,4,4-trimethyl-2-oxazoline and the like; reaction products of diamines or polyamine derivatives having a cyclic structure such as xylene diamine, N-aminopropylpiperidine, etc., with alkylene oxides; glycidyl ether adducts of polyoxyethylene alkylamine, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyethylene glycol, polypropylene glycol, polyoxypropylene alkylamine, spiroacetal series diamines, N-(aminoalkyl)-lactams or amines and the like.
The above desensitizers had a poor desensitizing effect and, because they lacked hydrophobicity, it was impossible to coat them using offset printing which is based on water repulsion.
Given the above, it has been desired in the art to develop hydrophobic desensitizers which possess strong desensitizing capability and which permit printing using generally used offset printers.